The present invention relates to a system for aiding in controlling current loss through a liquid column from a sprinkler head providing liquid to an electrostatic spraying system.
Various electrostatic spray systems have been advanced for spraying materials. U.S. Pat. No. 4,788,617 discloses an electrostatic spray system which utilizes two containers with liquid transfer between the containers. A sprinkler head adds makeup liquid to one tank. An electrostatic charge of high voltage is applied to a liquid in a second container and the liquid is then sprayed onto plants, for example. This device requires two closed pressurized tanks and requires control over the current flow between the tanks for operation. An induction ring is used around the sprinkler head output and is provided with a voltage of opposite polarity from the voltage providing the electrostatic charge. The induction ring voltage is controlled to reduce current flow back through the sprinkler head to ground.
An induction ring used around a sprinkler output in an electrostatic spray system is shown in U.S. Pat. No. 3,905,550. This induction ring is grounded directly.
It has been discovered that using an open-top container, and controlling the spacing between a head sprinkling liquid into the container and then providing an electrostatic charge to the liquid as it is pumped from the container provides a simplified construction if the container, the pump and other parts are isolated from ground through suitable insulators. In this arrangement, control of the size of the output from a makeup liquid sprinkler head can be controlled by a unique control ring.